Electrical flatiron



29, 1935. F w, CARPENTER 2,019,293

ELEQTRICAL FLATIRON Filed March `27. lzss :s sheets-sheet 1 Oct. 2 9, 1935. w. CARPENTER 2,019,293

ELECTRICAL yFLA'LIRON lFiled March 27, 19:53 s sheets-sheet 3 nasaaoeezaisss UNITED? size-rias montreal. mman Frank w. carpenter, man

polls. Minn-.Irn

or of one-half to Maurice H. Graham, St. Louis Park, Minn.

Applicaties Marsh yz-x, 193s, seringue. aan

1s clams. `(cl. zia-z5) My invention relates to the temperature conrol of electrically heated articles and is parlcularly directed to an improved means for the rons. Hence my invention is here illustrated in I ts application toV atirons.

An ideal'switch actuator or circuit controlleror electrically heated atirons, for example, is'

ne that will be influenced by and only by exansion and contraction of the sole plate or base..

To obtain such a result requires an'element or ontroller for the switch actuator that extends rom quite distant points. preferably from a.point Lear the heel to a point near the toe of the sole late.` If a metal or material could be found that Iould be absolutely 'free from expansion or conraction under the varying temperatures to whichhe iiatiron should be subjected in use. then the roblem couldbe easily solved; but so far as I am nformed, there is no material available, which, in

tself, has such non-expanding and contracting Lualities. f

Hitherto, the problem of thermostatic control of emperature of electrically heated flatirons'has` een solved in a more or less satisfactory way by wo schemes, to wit:

(a) By the use of a thermally expansible and ontractable switch actuating element, operated n accordance with temperature to which the said witch-actuating element was subj ected, but withut any definite relation to the temperature or xpansion and contraction of the sole plate or nember; and

(b) By an arrangement wherein a switch conrolling rod or bar of invar metal (assumed to lave no expansion and contraction under 'the 'arying temperatures) was'used as a switch conrol element. i

The first above noted scheme has been very unatisfactory for the reason that it has been pracically impossible to determine the exact andurii-l 'orm relative temperatures of the ilatiron base, 'or example, and the switch-actuating or con-r yrolling element, and from which it has followed yhat the regulation of the temperature of the sole :late of the atiron could not be accurately con- ;rolled. The second 'scheme has been found unatisfactcry, and in many instances entirely failed,

' electrically heated atiron. Y

' in practical performance. tor the reasons thatthe operating temperature of atiron bases should vary from 200 degrees F. to as much as 600 degrees F., and invar, while'it expands andcontracts very slightly at room temperatines,l does, at I temperatures above 200 degrees F.. expand very v considerably and at an unconstant and increasing rate as temperatures rise above 200 degrees F.

My invention makes a radical departure from the above noted schemes in that I provide and eni- 10 ploy a device herein designated as an expansion V neutralizer and which isl so combined with the switch of the electric supply circuit that any and all expansion. except that that takes place in the sole plate of the atiron, is neutralized and the 15 switch will be actuated solely by and in accordance with expansion and contraction in the sole plate. f

This arrangement makes it possible to control the application of heat to'the sole plate of the fflatiron to exactly the desired temperature. v 20 Further analysis of the invention and disclosure oi the nature thereof will be made in connection with theaccompanying drawings, which illustrate a commercial -embodiment oi the invention in an In the drawings', wherein like characters in cate like 'parts throughout the several views: y

Fig. 1 isa `perspective showingV the improved atiron embodying the invention; i

Flg.'2 is a perspectiveshowing -the sole plate, 30

the switch and immediately associated parts, the top portion of the iron beingremoved. 4 Y Fig. 3 is-a vertical section taken longitudinally and centrally through those portions of the iron X y that are illustrated in Fig. 2; some-parts being 35W Fig. 4' is a fragmentary view in plan of the partsshowninFig.3; .l

Fig. 5 'is a section taken approximately on the nnes-soimm- 40 'FigisadietailinsectiononthelineB-G of Fig. 5: v

Fig. 'I is a plan view showing thesole plate of the flatiron with-the insulating tiles and heating elements in place, but with other parts removed; '45

fFig. 8 is a perspective showing one of the insulating tiles removed from the sole plate; and l 9 is afragmentary sectioncta'ken on thel line -rl'of F18. 7.

I'he sole plate'of the iiatiron is indicated by 50 the numeral Il and may' take various forms. As shown, it is formed with a bifurcated central flange Ii that leaves spaces on each side thereof for the reception'of insulating tiles I2. These tiles are'made out of very light and porous re- 55 40 ment 22 is unail'eeted by expanding and contractrractory'matensi auch s ma from certain nent clays,`and on their under sides are formed with tortuous channels I2 that receive the heating elements Il, as best lshown in Fig. 9. Preferably,

-' with a lever 25 for oscillating the same to adjust these heating elements Il are coils of nichrome wire that are kept out of contact with the sole plate by said insulating tiles and by thin layers of cement I5 applied as best shown in Fig. 9.

The heating elements Il at their front ends are arranged to be connected through a switch k to be hereinafter described; but theirrear end terminais Il', see Fig. 2, are connected in the customary way to socket-engaging pins or terminals I6 mounted on a supporting bracket- I1 and insulated therefrom in the customary r well-known manner. Bracket I1 is .rigidly secured to the rear portion of central flange II.

The casing or upper portion I3 of the atiron as is usual, is a hollow shell. This shell and the handle I9 are shown as rigidly connected together and anchoredto the soie plate Il by a screw 2l that is engaged with a bridge baril, which in turn, is rigidly anchored to intermediate poi'- t tion oi the flange I I.

By reference to Fig. '1, it will be noted that the central flange I I is bifurcated Vto afford a central vcavity II. Located at the heel or rear portion of the sole plate and projecting into the rear portion of said cavity I Il is a rear abutment, which as shown, is afforded by the head 22 of a screw 23 that works through the rear portion of the sole plate and makes the said abutment 22 longitudinally adjustable for a purposewhich will hereinafter appear. As shown, the abutment screw 23 at its projecting rear end is provided the abutment.

Mounted loosely on the top of the front end of the sole plate I0 is a front abutment 25 the relative position of which with respect to rear abuting movements of the sole plate: but as shown, is prevented vfrom 'getting out of place by `causes other than expansion, by means of a screw 2B passed through an enlarged hole in said abutment 25 and screwed into the toe or front end of said sole plate. ".lhis front abutment 25, as will presently appear, constitutes an important element of the switch actuator proper.

To accomplish the above stated objects of my invention, it is necessary to provide means where-v by the so-called front abutment 25, regardless of expansions and contractions of the sole plateor other parts of the iron will maintain a constant unchanging position and distance from the socalled rear abutment 22. 'I'his I accomplish by the so-called neutraliser, a preferred form of which is illustrated in the drawings vand which, as shown, comprisesas follows:

A steel bar 21, preferably in the formof a channel, is loosely mounted on the top of theA sole plate I0; .and ailatbrass bar 28 is located within the channel and closely engaged with the top of said change or shift their relative positions. The rear end of bar 2l is shown as raised above the rear end o f bar21 for a'nimportant reason. A screw 30 that is screwed into the bar A21 and works loosely through a slot 3l in the bar 28, prevents the 'latvter from being lited from said bar 21, but without interfering with the diiferent expanding connecs tions of said. bars. A short lever 32 is fuicrumed in and works through a slot formed in the rear portion of the ba'r 21. The upper end of this lever has interlocking or other` contact with the raised rear end of bar 23 and the lower end of said lever is mounted on the stem of the screw 23 and is anchored against the head or abutment The switch herein may take different forms, butas here shown, is made up of two quite long contact arms 33 pivoted at 34 to lugs 35 yformed on the upper endsv of the side flanges of bar'21. At their free ends, these levers are shown as provided with fiat contact tips 36 that are insulated from the respective arms and are electrically connected to thin and very exible brass circuit-conducting ribbons 3 1 that are electrically connected to the front end terminals of the respec. tiye heating elements Il. A spring 33, shown as formed by a dat piece of spring steel bent into approximately c-shape, is connected to the respective arms 33 at its ends and exerts considerable force tending to hold the contact tips 36 engaged. At their pivoted ends, the levers 33 are provided with short inwardly projecting lugs `3il that come nearly but not quite into engagement.

The part herein designated as the switch actuator is in the form of a.v short upright lever v4I) located in a recess II formed in the toe or front end portion of the sole plate with the extreme lower endseated in the bottom portion of the sole plate, with its intermediate portion fulcrumed against the front'abutment 25, and with its extremeup- -per end engaged with the lugs 39 ofthe two switch levers33. In the particular arrangement umstratu, said lever 4o is provided with a, round lower end 42 resting in a seat 43 formed in and extended nearly but not quite'to the bottom of the sole plate so that the said lever l0 will be subject to expansion and contraction of the very bottommost portion of the sole plate.

At its intermediate portion, said lever i is extended through a slot M formed in the front end portion of bar 21 just in back of abutment 25, and the said abutment is shown as extended into a notch formed in the front edge of said lever. Lever Il, as shown, is round in crosssection and its extreme upper end 45 is flattened and is shown as made semi-cylindrical with its flat surface engaging the lugs 39' of switch levers 33.- Inasmuch as the switch levers 33are mounted for pivotal movement in a horizontal plane, the switch will not be jarred either open or closed when the iroii is roughly or abruptly set down or picked up.l

Summary of operation It has been stated that in accordance with this invention' (the preferred 'form only of which is herein illustrated) the front abutment 25 will be maintained always at an exact distance from the rear abutment 22 regardless of expansion and rcontraction of the various parts of the iron. The action of the expansion neutralizer, which makes the above result possible, is as followsz- 'Ihe twc bars 21` and 23 of this neutraliser are tiedptogether very close to or, if'desired,l at the froni abutment s o that, for example, there will be nc emcients of expansion. For example,

. 'amazes perceptible ensure in poseen ef said :rent abutment in respect to, for example, the rivet 29, which connects the two bars 21 and'28. When subjected to-heat. the two bars 21 and 28, being of different metals, have, of course, diiferent cowith the assumed metalssteel and brass. the brass bar 28 willexpand to a greater extent than the steel bar 21 and these relative rates of expansion will hold good throughout various different temperatures. It is important that the 28 be so closely associated f that they are subjectedl to the same temperatures, but the temperature to which they will be subjected relative to the temperature imparted to the sole plate of the iron is not at allimportant.

Under the resultant combined expansion of `the two bars 21 and .28, .lever 82 will be rocked rearward onthe abutment 22 to an obliqueposition, and when the proportions and arrangement olf said lever is correct, the expansion of both bars 21 and 28 will be entirely taken up by said lever 32. The exact proportions and arrangement of said lever 82 might quite readily be determined by a few experiments; but it may be more directly and accurately determined, as follows:

Take the lsaid elements 21, 28 and 32, while separated from the iron, and secure the front ends bars 21 andra to heat,

e distance from the bottom of bar 2 1;

of saidlevers and the attached front abutment 25 in a iixed position and then subject' the said hich will rock lever 32 to an oblique position, and then mark the oblique line represented .by said lever 82. Next, subject the bars 21 and 28 to a much lower degreeof tenperature, preferably v.lower than normal atmospheric temperatures, and mark the line represented by .the forwardly inclined oblique posinon or ea1d1ever. It win be round that thetwo obliquev lines marked to represent the extreme positions of said lever will intersect at a certam and that dls tance will indicate the proper length of said lever and the distance from the bar 21 that abutment 22 should be located. It must be seen vthat the expansion ofboth of bars 21 and 28 is taken up or compensated `for by movements of lever 32,

and that said lever, therefore, acts as the expansion take-up element offthe expansion neu- -tralizer made up of bars.

The rule forfdetermining the length of leverl 22 and location of its co-operating abutment. will hold good for the various different kinds of said lever andthe said two metals that may beused in the expansible bars of the expansion neutralizer. The length of expansion take-up element or-lever 32 will, of

- course, be modied by. various different factors.

For instance, it will be modified by the relative co-eillcient of yexpansion of the two metal bars and also by the distance, for example, that the rear end of bar 28 is raised above the underlying portion 4of bar 21 in which or against which said lever yis seated lor arranged to rock; .but when the ylength of lever has been determined, as above indicated, it will hold good for all of theyarying temperatures to which the expansion neutrallzer may be subjected, and the proper action of said device will not be affected by or have any relation to the temperature applied to the sole plate of the iron.

It has now been. shown that the front abutment 25 will maintain a nxed and unchanging position in respect to the rear abutment and to the rear portion of the sol'e plate, it becomes an, obviousmattcr that the supply switch will be tures thereof, said lever I8 will be rocked onthe two bars 21 and perature,

'ment 22 is attached.

ments close to :lected to varying of the sole plate and, moreover, by the expansion of the very bottom'portion of said plate. Normally, or when the sole plate is cold, and up to the time that mum temperature, the switch will remain closed. i When, however, the lower end of switch-actuating lever 48 is moved forward, by expansion of the sole plate, due to maximum d esired temperaabutment 25 (the latter operating as a fulcrum) andthe upper end of said lever by engagement with the lugs .38, will open the switch.

Even the maximum expansion of sole plate will represent only a few thousandths of an inch in movement and not sufllcient to` quickly or properly open the switch. Here it should be noted that, in the first place,vmovement imparted directly to lugs .29 will be multiplied about eight times through each lever 32, thereby causing each thousandth of an inch of expansion of the sole -plate to impart approximately sixteen-thousandths of an inch of separating movement to the contact tips 36. This will give the desired separating action of the contacts. 25

Obviously, when'the sole plate cools so as to reduce the temperature thereof but veryslightly below the predetermined desired maximum temthe switch will be again closed under the tension of thespring I8. Thus, as has been proven in practice, an electrically heated atiron may be kept substantially at constant desired temperature. This prede rmined desired maximum temperature, however, \may be varied by oscillating the screw`22 to which the rear abut- The insulating tiles l2, earlier described, not only afford the best kind of insulation for the electrical heating elements,

but properly position and place the heating elethe bottom of the lsole plate. 40-

Moreover, said tiles make possible aI atiron of very ligh weight which, of course, is known. to be a desirable feature.

From the foregoing, it will be understood that the invention illustrated m the drawings is capable of a wide range of modifications. Anfexf pansion neutra which, in itself is expansible and contractable, but which is arranged to -act in such manner as to definitely and unchangingly space distant abutments and the like when subdegrees of temperature, is thought to be broadly new andas such is here claimed. r What I claim is:

' l. An expansible and contractable body mem- 55 ber, electrical heating means applied to said body and including a switch, means for controlling the action of said switch including an expansion neutralizer which, in itself is expansible and` contractable, said neutraliz'er comprising heat reso sponsive members'tied together adjacent one end and having stant distance. regardless of such expansion and contraction and of expansion and contraction of said body, and a switch actuator operatively connected to'said body and to one of the fixed points of said expansion ne'utralizler.

2. The combination with an expansible and contractable body and means for applying heat thereto, of abutments, one of which is anchored tothe body and the other of which is located at a point distant from said anchored point, an expansion neutraliser wnnecting said abutments. 15

it reaches a predetermined maxi- 5 said neutralizar including two bars having different'co-efiicients of expansion tied together adjacent one of said abutments, and a lever connected to the other -abutment and to the free ends of said two bars. and a heat supply regulating element operatively connected to said body and cooperating with one of said abutments.,

3. An expansible and vcontractable body meming `tied togetheradjacent their connection with said last named abutment, anda lever connected to the other abutment and to the free ends oi said two bars and operative to compensate for the expvansion and contraction oi said bars and` thereby to maintain said abutments at constant distance regardless of expansion and contraction.

4. An expansible 'and contractable body member, electrical heating means applied to said body and including a switch, abutments, one of which is anchored to said body and the other or which is located at a point distant from said anchored point, a switch-actuating element connected to 4one of said abutments and to said body, and an expansion neutralizer connecting said two abutments and comprising two bars having diierent co-ei'licients of expansion", said bars being tied toy gether adjacent one of `said abutments, and a lever fulcrumed onto said otherabutment and connected to -said twoV bars. y

5. In a flatiron, the combination with the s'ole plate thereof and electrical heating means therefor including a switch, of front and rear'abutmenta-one anchored to the heel or rear end of said soie plate and the other slidably mounted on the toe or front end thereof, a switch-actuating element connected to saidfront abutment and to said sole plate, and an expansion neutralizar connecting said abutments and which, in itselL is expansible and contractable, said neutralizar 4comprising heat responsive members tied together adjacent said front abutment and having means connecting relatively movable portions oi said members to said rear abutment to maintain said` abutments at a constant distance regardless of such expansion and contraction'a-nd oi' expansion and contraction oi said body.

6. The structure dened in claim 4l in which said switch-actuating elementv is a lever, the lower end o! which is seated in the bottom of the body member; the'intermediate portion of which is fulcrumed against the co-operatng abutments, and the upper end of which i's directly operative on said circuit-controlling switch. i

f7. 'I'he structure deilned vin claim 4 in Ifurther combination withmeans ior'bodily adjusting one of said abutments with respect to the other to vary the degreeof temperature in said body member required to actuate said switch actuating element. 8. The structure deiined in claim 4 in which saidswitch-actuating element is a lever, the lower end'of which'is seated in the bottom' of the body member, the intermediate portion of which is i'ulcrumed against the co-operating abutment, and the upper en d of vwhich is directly operative on said s'witch, and further in which said switch comprises two-contact-carrying levers mounted actuating lever is fulcrumed.

1l. In a atiron, the combination with the sole plate thereof and electrical heating means therefor including a switch, oi vfront and rear abutments, the rear abutment being anchored to the sole plate and the iront abutment being free for movement withrespect thereto, a switch-actuating lever seated at its lower end` in the bottom portion' of saidsole plate and ficrumed to said front abutment, said switch including a lever mounted on a pivot adjacent and fixed in respect to said frontfabutment and having a short proiection arrangedto be engaged by the upper end of, said switch-actuating lever, and an expansion neutralizer connected to the front abutment andV comprising two metallic bars having different co-eilicients of expansion, said bars being tied together adjacent the front abutment, the free ends of said bars being separated, and a lever anchored at its lower end to said rear abutment with its intermediate portion fuicrumed to the free end of the bar having the lower co-eiilcient o1' expansionand with lits upper end connected to the free end of the bar having the higher co-eillcient of expansion.

12. In a ilatiron, the combination withv the' sole `plate thereof and electrical heating means therefor including a switch, of' a rear abutment anchored to the rear portion of said sole plate, a

i'ront abutment slidably'mounted at, the front portion of said sole plate soas to be free from expansion and contraction thereof, a switchto said front abutment,' and an expansion -neutralizer comprising two closely associated metallic bars having diierent co-elcients of expansion, the iront ends of said bars being tied together and connected tol said front abutment and the rear ends oi.' saidbars being free for expansion and contraction, and a lever connected to said rear abutment and to the free ends of said expans'ible bars, and arrangedto neutralize and absorb the expansion, and contraction or said two bars and maintain said two abutments spaced at constant distance regardless of expansion and vcontraction in said bars and sole plate, and whereby said vswitch actuator and switch will be operated by and in accordance with expansion and contraction 'of said sole plate.

13. The structure dened in claim 12 in which said switch includes a contact-carrying lever pivotally mounted adjacent the connected front ends of' the bars o! said expansion neutralizer and directy subject to the action of the upper end oi' said` switch-actuating lever.

14. An expan'sible and contractable body member, means carried by said body member for applying heat to said body member, an element carried in heat exchange relationship to said body element with respect to said body member, a secmember, anchoring means fixing a part of said' Y fildl-` v ehoringmeansi'ormaintainingfaremotepartot the ilrst element at substantially constant iis` tance from said means, and lever means ogier-l ativelyconnected to said body member and heat` applying means andswiveled to the remote part.

of said first element for maintaining said body member at substantiallyconstant temperature.

15. An expansible and contractable body member. means carried by said body member for applying heat to said body member, means for regulating said heat applying 'means comprising a lever operatively connected to said body member and to said heat applying means, and iuicrum means for said lever comprising a bimetallic ele-l ment having relatively movable portions and a portion iixed with respect thereto. said last mentioned portion having pivotal connection with said lever, and a second lever means connected to each of the relatively movable portions o! said plying heat thereto, a thermal compensating element carried in heat exchange relationship to said body member, said element comprising relatively movable parts and a part xed with respect thereto. Aa'lever connecting each ot the relatively movable parts oi' said element to a iixed 1o point on said body member, and means for regulating said heat applying means comprising a second lever swiveled to the iixed part of said elelment and anchored to said body. member at a point remote from said first mentioned lever, lo

whereby lto maintain said body member` at a substantially constant temperature.

y FRANK wicsnmm. 

